Iron Man’s reactor was powered by palladium before he rediscovered the made-up new element, Vibranium, because the palladium was poisoning him. Something similar may have happened with radioactive artificial hearts. (Iron Man 2 trailer)
Back in the 1960s, government scientists thought it was a good idea to make artificial hearts powered by the radioactive element plutonium-238.
This isotope of plutonium is the same one that NASA has used to power its space instruments — all the way from the experiments for the Apollo missions to Pluto’s probe, New Horizons.
Rebecca Harrington 